To test the long-term effects of a family and school intervention for the prevention of conduct problems in African American children enrolled in Pre-K programs in public elementary schools in socio- economically disadvantaged, urban communities. Rationale: Evidence documents that early conduct problems carry significant liability. They predict later antisocial behavior, and confer major disadvantage to children, families, and society. This application addresses this important public health concern. Hypotheses: Compared to no-intervention control, universal intervention will lead to fewer conduct problems in 1st and 2nd grade and better school functioning by 3rd grade. Parenting practices, teaching practices, parent-school involvement and child socio-emotional competence are predicted to mediate intervention effects on conduct problems and school functioning. Child and family risk factors are expected to moderate intervention effects such that high- risk children reap greater benefits than low-risk children. Design: Children from 10 schools with Pre-K programs in disadvantaged neighborhoods randomized to universal intervention or to a no-intervention control condition (N = 1040 4-year-olds) will be assessed in 1st and 2nd grade via observations of aggressive behavior and rule violations in the classroom, diagnostic interviews and parent and teacher reports. Achievement testing will be conducted in 1st and 2nd grade with record review in 3rd grade. Universal Intervention includes: 1) ParentCorps: After-school groups for families of Pre-K students co-facilitated by school personnel to promote effective parenting practices, parent-school involvement and child socio-emotional competence; and 2) TeacherCorps: Training for Pre-K, K and 1st grade teachers and other school personnel in classroom management, promotion of socio-emotional competence, and strategies for building family-school partnerships.